An ink-jet printer is a well-known one of image-forming apparatuses (or image-recording apparatuses) such as printers, facsimile machines, and copiers. The ink-jet printer performs recording on a recording medium such as paper (recording paper) by ejecting ink thereonto from a recording head. The recording medium is not limited to paper. The recording medium refers to a medium on which an image is formable. The recording medium may also be an OHP (overhead projector) sheet, for instance. The ink-jet printer can record a high-definition image at high speed with reduced noise at low running cost. Further, the ink-jet printer enjoys another advantage of easiness in recording a color image using multiple color inks.
An ink cartridge having a housing formed of a rigid rectangular shell and an ink reservoir filled with ink in the housing as disclosed in U.S. Pat. No. 5,788,388 (Prior Art 1) and an ink cartridge having a flexible bag-like ink reservoir with an ink outlet and a chassis (housing) with an opening through which the ink reservoir is insertable into and extractable from the chassis as disclosed in U.S. Pat. No. 5,860,363 (Prior Art 2) are well known as ink cartridges that are ink containing parts employed in the conventional ink-jet recording apparatuses.
FIG. 1 shows another conventional ink cartridge. The ink cartridge of FIG. 1 includes an ink containing part 501 containing ink, a cylindrical case 502 housing the ink containing part 501, and a lid member 503 covering the front side (opening) of the cylindrical case 502. The ink containing part 501 is integrated with a holding member 504 to which a sealed cylindrical ink filling opening 505 for filling the ink containing part 501 with ink and a cylindrical ink supply opening 506 for supplying ink are provided. The holding member 504 is pushed into the cylindrical case 502 so that projections 504a of the holding member 504 engage engagement holes 502a formed on the wall surface of the cylindrical case 502. As a result, the holding member 504 is fixed and held to the cylindrical case 502. The lid member 503 is fitted into the opening of the cylindrical case 502.
Recent ink-jet recording apparatuses tend to consume more ink as higher image quality is achieved. Therefore, in the recent ink-jet recording apparatuses, a small sub tank is mounted on a carriage so that ink is supplied to the small sub tank from a main ink cartridge provided to the apparatus main body. This is because a conventional type of ink-jet recording apparatus in which cartridges are mounted on a carriage requires frequent replacement of cartridges.
Accordingly, ink cartridges have become larger in size, and if the ink cartridges should be disposed of directly after use as the above-described ink cartridge disclosed in Prior Art 1, it is a huge waste of resources. Therefore, it is necessary that ink cartridges be effectively reusable.
The ink cartridge of Prior Art 2 simply houses an ink reservoir in a chassis so that the ink reservoir is insertable into and extractable from the chassis. According to this configuration, however, the ink reservoir remains unstable, thus preventing a stable supply of ink. In the case of inserting the ink cartridge into the main body of an apparatus from its upper side so that the ink cartridge is loaded into the apparatus with the ink supply opening of the ink cartridge facing downward, the ink reservoir is stabilized to some extent in the chassis. However, in the case of inserting the ink cartridge into the main body of the apparatus from its front side so that the ink cartridge is loaded with its ink supply opening facing in a sideward (horizontal) direction (hereinafter, this configuration is referred to as a front loading configuration), the ink reservoir is inclined in the chassis. Accordingly, it is impossible to employ the front loading configuration with such an ink cartridge.
Further, in the case of the ink cartridge of FIG. 1, the holding member 504 holding the ink containing part 501 has to be pushed into or extracted from the cylindrical case 502 through its opening that is substantially equal in size to the holding member 504. Therefore, the ink cartridge is assembled or disassembled with poor operability. Further, in the case of pouring ink into the ink reservoir, stability is not maintained if the ink reservoir is extracted from the chassis 502. On the other hand, if the ink reservoir is placed in the chassis 502, it is impossible to check the condition of the ink bag 501 while pouring ink into the ink reservoir.
Further, the ink-jet recording apparatuses have been widely used for business purposes because of their increasing processing speed. Therefore, it is required to reduce costs per print, which has been realized by increasing the capacity of an ink cartridge.
However, users who print out a relatively small number of prints and thus consume a small quantity of ink cannot use up ink in the ink cartridge of a large capacity before a recommended expiration date of the ink. As a result, the ink may deteriorate over time to cause ejection instability. Further, the unit purchase price of ink cartridges rises, so that an ink cartridge generally coming with the purchase of an apparatus also becomes expensive, thus placing a burden on users.
Moreover, in order to improve the assemblability and disassemblability of an ink cartridge, to make it possible to check the condition of an ink bag, and to make the front loading configuration employable, a dividable housing may be proposed for an ink cartridge. In the case of employing a dividable housing, however, the rigidity of the housing is reduced.